In a recent article I explained why it is impossible to recover data from a hard drive after overwriting it. In that post I mentioned that simply deleting files or formatting your hard drive typically does not remove or overwrite files at all, meaning they can still be recovered.

If this information made you a little nervous, let me connect the pieces for you and show you how you can terminally and permanently delete files, not only from your hard drive, but also from other re-writable storage devices.

Low Level Formatting

The kind of formatting most of us do is known as high level formatting, and whether you perform a quick format or not, your data won’t be deleted. What high level formatting does is set up the file system from scratch and in the process the information where files were stored is removed.

Low level formatting on the other hand re-initializes the disk and resets the values of each and every magnetic domain, which represents one bit, to zero. We have thoroughly covered formatting on MakeUseOf and if you would like to look into the details, I recommend the following articles:

Low level formatting isn’t 100% efficient and may leave traces of data. If you wish to wipe an entire disk before you dispose of it, I recommend Darik’s Boot and Nuke, a boot disk that will automatically and completely delete data on any detected hard disk.

If you are already using CCleaner, you should know that it contains a Drive Wiper.

Open CCleaner and go to > Tools > Drive Wiper. You can wipe only free space or the entire drive, and you can choose up to 35 passes, meaning data will be overwritten with random strings of binary code 35 times. This very complex overwrite should make it impossible for anyone to restore the data originally saved in this space. When you’re happy with your settings click > Wipe and wait patiently.

Microsoft made it very easy to not delete files thoroughly. To make up for this potential security hole, they released a free command line utility called SDelete. This doesn’t make removing data any more convenient, but it can be considered a step in the right direction. Unfortunately it is a very small step, since Microsoft fails to provide instructions on how to properly open SDelete in the first place. Well, that’s what MakeUseOf is here for.

Download the ZIP archive containing the tool and extract the folder.

Click > [WINDOWS] + [R] to open the Run window.

Type > cmd and click > OK to open the command prompt.

Then move the > SDelete.exe file to the directory > C:\User\yourusername

Now type a command in the command prompt, for example > sdelete -z to cleanse free space on your C: partition. A full list of commands is shown in the screenshot below.

Eraser is a freeware and open source security tool to completely remove data from your hard drive. It can overwrite data several times using randomized patterns of binary code. It essentially is a file shredder.

Eraser is more convenient than CCleaner’s Drive Wiper because it can delete and shred single files, rather than just wiping all free space on a drive, and it is integrated with Windows Explorer (right-click menu). Moreover, Eraser provides you with a host of advanced settings, for example different file and space erasure methods, the option to replace erased files with other files to allow plausible ‘deniability’, and schedule erasure of files, folders, recycle bin, or unused disk space.

The tool is also available as a portable app called EraserDrop Portable. It is part of the PortableApps suite.

Confusion is the order of the day in the preceding proceedings above, because their is (to my estimation) no clear delineation which would clearly differentiate between simple delete
(which in my opinion only means HIDE) as compared to other modality.
When Monica Lewinsky ‘deleted’ Bill Clinton’s emails
twice (as is usually the case for most situations)
she apparently thought that said emails were irretrievably
gone. Computer “experts” easily recovered those supposedly
‘deleted’ emails.Actually even a novice can recover similarly
‘deleted’ files by downloading ,installing and using
available online recovery freeware.

The use of the term “low-level format” should be rejected
as it no longer reflects modern hard drive reality.
If one is dreaming off “low level formatting” the S.M.A.R.T
ability of a hard drive, he’d better give up dream that
dream.
Over-writing existing data over an entire drive
with random 1s and 0s should be called a mid-level format
as the fundamental sector of that drive dedicated to
the specific manufacturer’s data or instructions
is made inaccessible to users by design.

By the way,one can just use 0s everywhere
(instead of 1s and 0s) to overwrite data you never want to see again;such a case is appropriately called to
“ZERO_OUT the drive”.

A simple freeware such as Killdisc 8.0 will “zero_out” your drive. I use the DOS version,but a Windows suite version is also available (among others).
One must however realize that a “zero”ed_out drive
will not be usable until one FORMATs the drive with a chosen file
system and also newly INSTALLs a chosen operating system.

Apparently the DOD of our USA “supposedly”
requires 7 over_writes (as per its own algorithm)
so as not to miss any sensitive data that could (at least in theory) be retrievable.

I have encountered many hard drives, supposedly defective,
supposedly harboring bad sectors, but which subsequently
functioned well after being ZEROed_out,FORMATTED,
and newly loaded with an OS.
One negative in the picture is “how long it takes”
to zero_out a drive when one is dealing with Terrabytes hard drives.

If one is concerned that his wife will accidentally discover
that he had actually been visiting porn sites while allegedly
“doing computer work”, he should indeed wipe out
all traces of his indiscretions.
I will let someone else discuss whether or not using
wipe_out (or other “secure” mean of erasure)
actually affects the total USABLE space on the hard drive.

Hi Tina,
Nice article. I am curious tough on why CC cleaner gices the possibility to overwrite data up to 35 times in order to make it impossible for any expert to reconstruct the initial data, while on the other hand you state in your instroductiona nd other article that it is impossible to retrieve overwritten data.

Well, it is impossible for the average user to retrieve data that was overwritten. With advanced technology, however, it is possible to reconstruct data.

I don’t know how exactly this works, but I imagine that every re-write leaves its trace (magnetic on a hard drive) and with adequate scanning techniques, those traces can be filtered until readable data have been extracted.

I have delete a personal text file and also empty recyclebin after than i have delete other text file exist same name and once again empty recyclebin for overwrite first personal file now is the possible recover the first personal text file from hard disk????

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This review may contain affiliate links, which pays us a small compensation if you do decide to make a purchase based on our recommendation. Our judgement is in no way biased, and our recommendations are always based on the merits of the items.